Assessment of autonomic nervous function in human hypertension

In spite of the popular belief that "nervous tension," "stress," and hypertension are causally related, it has been difficult to prove a role of autonomic dysfunction in the genesis of essential hypertension. There are three major reasons for this: 1) autonomic function cannot be assessed with one simple test, 2) the short-term "phasic" and long-term "tonic" autonomic control of blood pressure are not necessarily interrelated, and 3) hypertension is a dynamic process in the course of which there are changes in autonomic control. Some of the controversies in the field stem from the lack of appreciation of these limitations.